The "suggestion"/error wants you to have the memorial ID number. The template is useful because Ales, the tech guy, is planning to update it as needed using bots in case the URLs change in the future (a possibility, since Find a Grave made so many recent changes).
Personal Preference here: To me, it's important to include a complete citation for each source I use, so for your Thomas Hopkins, I would include the complete citation from Family Search:
"Find A Grave Index," database, FamilySearch(https://familysearch.org/ark:/61903/1:1:QV2P-TYBW : 13 December 2015), Thomas Hopkins, 1807; Burial, Argyle, Washington, New York, United States of America, Hopkins Cemetery; citing record ID 74467288, Find a Grave, http://www.findagrave.com.
Then I would replace this bit: Find a Grave, http://www.findagrave.com which is fairly useless with the template. {{FindAGrave|74467288}}
I pretty much love the template.
Anyway, if you slap the memorial number on, using your current format, that will work too. Just make sure you use the memorial number, mark the error corrected, and blissfully continue to add profiles, knowing you have one less suggestion to deal with.